Marion Le Gall, PhD
Nutritional Ecology of Herbivorous Pests
For as long as I can recall, I have loved insects. As a researcher, the intricate relationship between insects and their diets captivates me. I find herbivores particularly interesting because they manage to balance multiple and evolving nutrient needs while feeding on plants. Plants are a challenging food because their nutrient composition is dynamic and generally does not match animal body composition.
To understand how herbivorous insects solve these challenges, I use a physiological approach called the Geometric Framework for Nutrition (GFN). It is a conceptual model that focuses on the geometric relationship between nutrient intake and physiological needs, providing insights into the trade-offs and constraints that shape an organism's dietary requirements. I use the GFN as a window into the underlying mechanisms shaping ecological patterns and processes, both within controlled lab settings and also out in the field with dynamic variables. Notably, I use the GFN in agricultural settings with herbivorous pests.
FAO estimates that between 20-40% of global crop production is lost to pests annually. The overarching goal of my research is to bridge the gap between theory and application and develop sustainable management programs for insect pests. I strongly believe that integrated pest management (IPM) is key for long-term food security, ecological health, and responsible resource use.
Research Interests
In the Geometric Framework for Nutrition, nutrients that an herbivore eats are modeled in a geometric space. This method yields a visual and quantitative representation of how variation in nutrients affects food preference. An animal's performance can also be mapped onto a geometric space to determine how nutrients impact variables like growth, reproduction, dispersal, etc. This framework was developed in the lab with laboratory colonies, however for my research, I also apply it in the field with wild insect populations. Thanks to this integrative approach, I have been able to better understand the basic nutritional biology of economically damaging pest species and help farmers find solutions to herbivorous pest problems in West Africa, Australia, and the United States.
Publications
Brosemann, J. K., Overson, R., Cease, A. J., Millerwise, S. C., & Le Gall, M. Nutrient supply and accessibility in plants: effect of protein and carbohydrates on Australian plague locust (Chortoicetes terminifera) preference and performance. Frontiers in Insect Science, 3, 1110518.
Le Gall, M., Touré, M., Lecoq, M., Marescot, L., Cease, A., & Maiga, I. (2023). Senegalese grasshopper—a major pest of the Sahel. In Biological and Environmental Hazards, Risks, and Disasters (pp. 77-96). Elsevier.
Le Gall, M., Boucher, M., & Tooker, J. F. (2022). Planted-green cover crops in maize/soybean rotations confer stronger bottom-up than top-down control of slugs. Agriculture, Ecosystems & Environment, 334, 107980.